Pulse the garlic in a food processor until minced. Scrape the bowl and add the lemon juice and a sprinkle of lemon zest. Set aside for 10 minutes for the garlic to mellow in flavor (optional).
Toast the coriander and cumin seeds (if using) over low heat in a skillet for about 2 minutes, or until fragrant. Transfer to a mortar and grind them until a powder forms. Set aside.
Transfer the tahini and ice water to the food processor and pulse until smooth.
Add the beans, coriander, cumin, and miso. Pulse until smooth, scraping the bowl occasionally.
With the machine running, add the olive oil until the desired creaminess. Season with salt to taste.